Field
The present invention relates to detector circuits, e.g. for impedance measurement systems.
Background
Impedance measurement systems can be used to determine the impedance of a signal path in a mobile communication device where the signal path's impedance depends on its external conditions. In other words, where the signal path has a variable load impedance. In the case of mobile communication devices with an antenna, the variable load impedance can be due to the antenna's changing environment.
In order to optimize the transmission coefficient of transmit (Tx) or receive (Rx) signals propagating in the signal path, the signal path's actual impedance must be known.
Conventional impedance measurement systems use two receive signal strength indicator (RSSI) chains as level detectors to measure two signal levels. An additional phase detector is needed to measure the phase between the two signal levels.
It would be desirable to provide a detector circuit for an impedance measurement system, without the need for an additional phase detector and without the need for a level detector, e.g. an RSSI-chain.